protected override async Task OnMessageActivityAsync(ITurnContext <IMessageActivity> turnContext, CancellationToken cancellationToken) { if (turnContext.Activity.Attachments != null) { var url = turnContext.Activity.Attachments[0].ContentUrl; var transcribed = await SpeechRecognizer.RecognizeSpeechAsync(url); if (transcribed != "") { await turnContext.SendActivityAsync("You said: " + transcribed); } turnContext.Activity.Text = transcribed; } else { await turnContext.SendActivityAsync("I can understand voice messages, try me."); } }